AAT3142ITP-T1 AnalogicTech, AAT3142ITP-T1 Datasheet

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AAT3142ITP-T1

Manufacturer Part Number
AAT3142ITP-T1
Description
High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications
Manufacturer
AnalogicTech
Datasheet
General Description
The AAT3142 is a low noise, constant frequency charge
pump DC/DC converter that uses a tri-mode load switch
(1X), fractional (1.5X), and doubling (2X) conversion to
maximize efficiency for white LED applications. The
device produces current levels up to 30mA on each of its
three current source outputs to drive various arrange-
ments of LEDs from a 2.7V to 5.5V input. Outputs may
be operated individually or in parallel for driving higher-
current LEDs. A low external parts count (two 1μF flying
capacitors and two small 1μF capacitors at V
make the AAT3142 ideally suited for small battery-pow-
ered applications.
AnalogicTech’s Simple Serial Control™ (S
input is used to enable, disable, and set the LED drive
current with a 32-level logarithmic scale LED brightness
control. The AAT3142 has a thermal management sys-
tem to protect the device in the event of a short-circuit
condition at an output pin. Built-in soft-start circuitry
prevents excessive inrush current during start-up. A high
charge pump switching frequency enables the use of
very small external capacitors. In shutdown mode, the
device disconnects the load from V
cent current to less than 1μA. The AAT3142 is available
in the very small, Pb-free 12-pin TSOPJW package.
Typical Application
ChargePump
3142.2009.07.1.3
V
BATTERY
TM
High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications
IN
and reduces quies-
C
1μF
IN
2
Cwire™) digital
EN/SET
IN
w w w . a n a l o g i c t e c h . c o m
and CP)
C
1μF
CP
VIN
CP
EN/SET
AAT3142
Features
• V
• Tri-Mode 1X, 1.5X, and 2X Charge Pump for Maximum
• Drives Low-V
• Up to Three 30mA Outputs
• 32-Position Logarithmic Scale with Digital Control
• Low Noise Constant Frequency Operation
• 1MHz Switching Frequency
• Small Application Circuit
• Regulated Output Current
• Automatic Soft Start
• No Inductors
• I
• 12-Pin TSOPJW Package
Applications
• Color (RGB) Lighting
• Programmable Current Sources
• White LED Backlighting
• White Photo Flash for Digital Still Cameras
Efficiency and V
GND
Q
IN
< 1μA in Shutdown
Range: 2.7V to 5.5V
C1+
C1-
C2+
C2-
D1
D2
D3
F
and High-V
F
Coverage
PRODUCT DATASHEET
D3
C1
1μF
C2
1μF
F
Type LEDs
D2
AAT3142
D1
1

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AAT3142ITP-T1 Summary of contents

Page 1

... V make the AAT3142 ideally suited for small battery-pow- ered applications. AnalogicTech’s Simple Serial Control™ (S input is used to enable, disable, and set the LED drive current with a 32-level logarithmic scale LED brightness control. The AAT3142 has a thermal management sys- tem to protect the device in the event of a short-circuit condition at an output pin ...

Page 2

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Pin Descriptions Pin # Symbol Function 1 C2+ Flying capacitor 2 positive terminal. Connect a 1μF capacitor between C2+ and C2 Charge pump output. Requires 1μF capacitor ...

Page 3

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Absolute Maximum Ratings Symbol Description V Input Voltage IN V EN/SET to GND Voltage EN/SET I Maximum DC Output Current 2 OUT T Operating Junction Temperature Range J Thermal ...

Page 4

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Electrical Characteristics 1.0μ -40°C to +85°C, unless otherwise noted. Typical values are ...

Page 5

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Typical Characteristics V = 3.5V 1μ Efficiency vs. Input Voltage (Code 26) 100 90 3.0V ...

Page 6

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Typical Characteristics V = 3.5V 1μ Turn-On to 1.5X Mode (3x30mA Load) EN/SET (2V/div) V ...

Page 7

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Typical Characteristics V = 3.5V 1μ Load Switch to Charge Pump (1.5X Mode, 3x19mA Load) ...

Page 8

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Typical Characteristics V = 3.5V 1μ Load Characteristics (1.5X Mode, 3x15mA Load (20mV/div) ...

Page 9

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Functional Block Diagram EN/SET Functional Description The AAT3142 is a tri-mode load switch (1X) and high efficiency (1.5X or 2X) charge pump device intended for white LED backlight applications. ...

Page 10

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Applications Information Constant Current Output Level Settings The constant current source amplitudes for are set via the serial interface according to a logarithmic scale where each ...

Page 11

... S Cwire Serial Interface 2 The current source output magnitude is controlled by the EN/SET pin, using AnalogicTech’s S interface records rising edges of the EN/SET pin and decodes them into 32 individual current level settings with Code 1 reserved for no current. Once EN/SET has been held in the logic high state for time T grammed current is seen at the current source outputs, and the internal data register is reset to 0 ...

Page 12

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Since the AAT3142 outputs are pure constant current sources and typically drive individual loads difficult to measure the output voltage for a given output (D1 to D3) ...

Page 13

ChargePump High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications TM Capacitor Selection Careful selection of the four external capacitors and C is important because they will affect turn-on 2 OUT time, output ripple, and transient performance. ...

Page 14

... Marking Part Number (Tape and Reel) 1 PJXYY TSOPJW-12 0.20 + 0.10 - 0.05 7° NOM 4° ± 4° 0.055 ± 0.045 0.010 PRODUCT DATASHEET AAT3142 2 AAT3142ITP-T1 0.04 REF 0.45 ± 0.15 2.75 ± 0.25 3142.2009.07.1.3 ...

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